Sling



FIG. 1 is a perspective view;

FIG. 2 is a top plan view;

FIG. 3 is a bottom plan view;

FIG. 4 is a right side view;

FIG. 5 is a left side view;

FIG. 6 is an end view; and,

FIG. 7 is an opposite end view.

The broken lines in FIGS. 1-7 are for environmental purposes and form no part of the claimed design. 

CLAIM The ornamental design for a sling, as shown and described. 